sharing-gallery/html/style.css

html {
  height: 100%;
  width: 100%;
}

body {
  padding: 2.25em 0 0 0;
  margin: 0;
  height: 100%;
  width: 100%;
}

div#header {
  opacity: 1;
  position: fixed;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  align-content: flex-start;
  font-size: 150%;
  top: 0;
  left: 0;
  right: 0;
  padding: 0 .1em 0 .1em;
  margin: 0;
  height: 1.5em;
  background-color: black;
  color: white;
}

h1 {
  margin: 0;
  padding: 0;
  font-size: inherit;
  display: inline;
  flex: 1;
  align-self: flex-start;
  text-overflow: ellipsis;
  white-space: nowrap;
  direction: rtl;
  text-align: left;
  overflow: hidden;
}

#arrows {
  flex: 0 0 auto;
}

a:link, a:visited, a:active, a:hover {
  text-decoration: inherit;
  color: inherit;
}

input[type="checkbox"] {
  display: none;
}

input[type="checkbox"] + label {
  opacity: 0.5;
  border: .25em solid black;
  border-radius: 1em;
}

input[type="checkbox"]:checked + label {
  opacity: 1;
  border: .25em solid yellow;
  border-radius: 1em;
}

img {
  width: auto;
  height: auto;
  max-width: 100%;
  max-height: 100%;
}

div.image {
  width: 100%;
  height: calc(100% - 2.25em);
  background-color: black;
  text-align: center;
}

img.image {
  display: block;
  margin: auto;
  object-fit: contain;
  object-position: 50% 50%;
}

div.images {
  color: white;
  background-color: black;
  padding: 2em;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-around;
  align-items: center;
  align-content: space-around;
}

div.images img.thumbnail {
  padding: .5em;
  margin: .5em;
  box-shadow: .2em .2em .6em #aaa;
  border-radius: 1em;
  background-color: white;
  flex-grow: 1;
  flex-shrink: 1;
  flex-basis: auto;
  align-self: center;
}